Polymeric materials are used in a wide variety of applications, for example, in the production of different plastic objects or in coatings for surfaces. A recurring issue with polymeric materials is that they tend to fail or degrade due to mechanical fatigue, mechanical impact, oxidative aging, thermal fatigue, chemical degradation, or a combination of these processes. The degradation can lead to embrittlement of the polymer and associated cracking. Mechanical fatigue and mechanical stress can also lead to cracks in the polymeric material. When cracks occur in a polymeric coating on a metal surface, the underlying metal surface can be exposed to the elements and be subject to corrosion.
Recently there have been developed “self-healing” polymeric materials that can repair cracks or other damage in the materials after they occur. There is widespread interest to use such materials in the coating industry for corrosion mitigation and in other applications. Generally the self-healing polymeric materials are comprised of a polymer matrix and two separate kinds of microcapsules dispersed in the matrix. The first microcapsules include a core containing a reactive oligomer and the second microcapsules include a core containing a catalyst. The first microcapsule releases the reactive oligomer upon stress and the oligomer flows into the crack and polymerizes upon contact with the catalyst released from the second microcapsule Implementation of this two-part catalyzed cure microencapsulation technology for self-healing coating development has been challenging due to the complex curing mechanism of the coatings and other issues. There is still a need for improvements in self-healing polymeric compositions.